This application seeks for a meeting on the effects of combined radiotherapy and chemotherapy in the treatment of malignant disease. The meeting is planned for November 1978 at Hilton Island, South Carolina. This meeting is the sixth in a series of meetings designed to improve radiotherapy through the application of basic science and advances in other fields. The last such meeting was held in Greenbrier, West Virginia, in March 1974 on the topic of the interaction of radiation host immune defense mechanisms in malignancy. The proposed meeting is based on this tradition and on the recognition of the extreme importance of understanding the role of combinations of radiation and chemotherapy in the improved management of malignant disease. The research plan for radiation oncology emphasized the need for increased studies in this area and the need for a national meeting bringing together radiation oncologists, chemotherapists, and basic scientists to speed the application of chemotherapy to radiotherapy. The proposed meeting will bring together those working in the field of drug development, clinical chemotherapy, radiobiology, clinical radiotherapy, and members of cooperative clinical trial groups in order to augment the information available in combined radiotherapy-chemotherapy and to speed the application of basic knowledge to developing clinical trials.